Like other forms of 3D printing, bio-printing lays down layer after layer of material -- in this case, live cells -- to form a solid physical entity -- in this case, human tissue. The major stumbling block in creating tissue continues to be manufacturing the vascular system needed to provide it with life-sustaining oxygen and nutrients. ... Organovo, however, said it has overcome that vascular issue to a degree.

The liver won't be suitable to be used as transplants in human beings. But it will be effective for scientific research and drug testing, Mike Renard, Organovo's executive vice president of commercial operations told Mearian.

That could be good news for Organovo's investors. It hopes to sell the 3D printer to drug companies to help them reduce the costs of drug testing. On average, it cost $1.3 billion to develop a new drug in 2013, according to research from Deloitte and Thomson Reuters.

The company says it can't predict when its engineered tissues might be used in live humans. It sent us this statement: "We are developing a human liver tissue model for medical research and drug discovery testing. We have not provided any information on when engineered tissues might be used as future therapeutic solutions."

But if this works as advertised, it could be a game-changer for the company, its investors, and potentially the human race.

Via a YouTube video, Organovo explained how its special bioprinting technology works. It starts with special "bio-ink" and works with cells from any source.

If you looked inside these wells, you'd see the natural tissues grow. It looks like this:

The tissue doesn't look like a full organ, but the tissue samples should have the organ's properties. Scientists can infect those tissues with disease and then infuse them with different drugs.